1. Field
The embodiments relate to an organic light emitting device having improved light emitting quality by reducing leakage current between pixels.
2. Description of the Related Art
In recent years, organic light emitting devices are being spotlighted in the field of display technology. The organic light emitting devices emitting light, which is generated when electrons and holes are coupled together and then diminish.
The organic light emitting device basically includes an electrode for injecting holes, an electrode for injecting electrons, and a light emitting layer. The organic light emitting device has a structure in which the light emitting layer is stacked between an anode, i.e. the electrode for injecting the holes, and a cathode, i.e. the electrode for injecting the electrons. In more detail, electrons are injected in a cathode of the organic light emitting device and holes are injected in an anode of the organic light emitting device. When the charges (holes and electrons) are moved in opposite directions by an external electric field, are coupled together in a light emitting layer, and diminish, light is emitted. The light emitting layer of the organic light emitting device includes an organic monomer or an organic polymer.
In recent years, as resolutions of displays are getting higher, resolutions of the pixels (ppi) have increased, and the interval between the pixels have gradually decreased. Further, in recent years, as efficiencies of light emitting materials for organic light emitting devices are increasing, a high brightness can be achieved with a low current and a low voltage, making it possible to lower power consumption. However, as light can be emitted by a small amount of current (due to a high efficiency of a light emitting material for an organic light emitting device) light may be emitted by a very small amount of current leaked from one pixel to another adjacent pixel. As a result, an adjacent pixel, which is not intended to emit light, often emits light.
The light emitted due to leakage currents is referred to as leakage emission light. If the leakage emission light is generated, a color mixture is generated and a color coordinate is changed. In addition, when the leakage emission due to a leakage current is generated in a low-brightness region, black brightness may increase.
In particular, a green light emitting material has a high efficiency. Thus, when a red pixel or a blue pixel adjacent to a green pixel is driven, the adjacent green pixel may emit light due to current leakage from the red or blue driven pixel.
The leakage emission light is one of the phenomena generated as an efficiency of a light emitting material and a resolution of a display increase. Accordingly, a method of lowering an efficiency of a light emitting material or lowering a resolution of a display device may be adopted to restrain a leakage emission light. However, a demand for low-power/high-resolution products has also increased in recent years. As such, the problem of leakage emission light must be resolved without lowering the efficiency of a light emitting material or lowering the resolution of a display device.
Therefore, a technology for restraining a leakage emission light due to leakage currents, without lowering a resolution of a display unit using a high-efficiency light emitting material is needed.